Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753767AbbFARb4 (ORCPT ); Mon, 1 Jun 2015 13:31:56 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:36092 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753716AbbFARbq (ORCPT ); Mon, 1 Jun 2015 13:31:46 -0400 Date: Mon, 1 Jun 2015 19:31:58 +0200 From: Darren Hart To: Bruno =?iso-8859-1?Q?Pr=E9mont?= Cc: Michael Marineau , Bjorn Helgaas , platform-driver-x86@vger.kernel.org, "linux-kernel@vger.kernel.org" , Petri Hodju , Matthew Garrett , "linux-pci@vger.kernel.org" Subject: Re: [Patch v3] apple-gmux: lock iGP IO to protect from vgaarb changes Message-ID: <20150601173158.GA87111@vmdeb7> References: <20150307011546.0050279d@neptune.home> <20150309225238.0b9ced4e@neptune.home> <20150311223445.6af76f7c@neptune.home> <20150527044749.GB21644@fury.dvhart.com> <20150527081323.35a3cf88@pluto.restena.lu> <20150529163650.GA94698@vmdeb7> <20150601082227.01663ac8@pluto.restena.lu> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20150601082227.01663ac8@pluto.restena.lu> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1444 Lines: 34 On Mon, Jun 01, 2015 at 08:22:27AM +0200, Bruno Pr?mont wrote: > On Fri, 29 May 2015 18:36:50 +0200 Darren Hart wrote: > > > Making sure to lock only the intel GPU when present and especially protecting > > > against nvidia driver will be hard if legacy-IO is being processed by a hidden > > > device! > > > > Ugh indeed. Worst case we can special case via dmi strings. Is this Apple device > > significantly different from others? Bruno, what are you testing on? > > I only own a pretty old MacBook Air with just NVIDIA IGP and had to > rely on BUG reports and testing from affected users. > > Not doing anything on apple-gmux when only a single GPU is visible > should be easy, but denying any vgaarb operation when Intel IGP is > hidden and just discrete GPU present is much harder (if one does not > want to risk opening the next can of worms). > > DMI based special-casing would work but will it uncover the next issue > with the same device configured differently? No, we would need a combination. I presume "configured differently" would mean the Intel GPU present - which would be detectable. DMI + Nvidia = do A DMI + Intel = do B -- Darren Hart Intel Open Source Technology Center -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/